This article introduces one of the most important topics in WordPress development: WordPress hooks, including action hooks and filter hooks. Hooks are at the core not only of how WordPress plugins work, but nearly all code in the WordPress ecosystem: most WordPress themes use hooks heavily, as does “WordPress core” itself. WordPress hooks are absolutely a must-know topic in WordPress development.

This course covers one of WordPress’s most crucial and widely used systems: Hooks, including both actions and filters. We introduce Hooks as an event-driven system, present the key concepts and terminology you need to understand this system, and dig deep into how to use hooks in your own code—including hooking in your own functions, removing previously hooked functions, and creating your own action and filter hooks for others to use.

How does a single plugin become the basis of a thriving technology ecosystem? Partly by leveraging the extensibility that WordPress’s event-driven Hooks system makes possible.

WordPress’s hook system is an example of an “event driven” architecture or programming system.